Failed supernova remnants

Abstract In a failed supernova, partial ejection of the progenitor’s outer envelope can occur due to weakening core’s gravity by neutrino emission in protoneutron star phase. We consider when this ejecta sweeps up circumstellar material, analogous supernova remnants (SNRs). focus on explosions blue supergiants, and find that be bright soft X-rays. Due its emission, we sources Large Magellanic Cloud (LMC) are more promising for detection than those Galactic disk. These characteristic their small size (?10 pc) slow speed (100s km s?1) compared typical SNRs. Although expected number detectable is (up few eROSITA four-year all-sky survey), prospects better deeper surveys targeting LMC. Detection these “failed SNRs” will realize observational studies mass following black hole formation.